ACTG 347 - 141W94/VX-478 is an investigational drug under development by Glaxo, Inc. This study is proposed to test the hypothesis that monotherapy with 141W94/VX-478 doses that result in C min levels far in excess of the IC90 corrected for plasma protein binding for HIV-1 can achieve the same virological and immunological effects in terms of magnitude and durability as has been observed with combinations of other protease inhibitors plus nucleoside analogs.